ICTV Virus Taxonomy Profile: 2025.

The realm includes viruses of archaea, bacteria and eukaryotes, with linear dsDNA genomes. Duplodnavirians share a distinct morphogenetic module of four hallmark genes encoding the HK97-fold major capsid protein, a genome packaging ATPase-nuclease (large terminase subunit), a portal protein and a capsid maturation protease. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the realm , which is available at ictv.

Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Bacterial Viruses Subcommittee, 2025.

This article summarises the activities of the International Committee on Taxonomy of Viruses Bacterial Viruses Subcommittee, detailing developments in the classification of bacterial viruses. We provide here an overview of all new, abolished, moved and renamed taxa proposed in 2024, approved by the Executive Committee, and ratified by membership vote in 2025. Through the collective efforts of 74 international contributors of taxonomy proposals in this round, 43 ratified proposals have led to the creation of one new phylum, one class, four orders, 33 families, 14 subfamilies, 194 genera and 995 species.

Virus taxonomy proposal summaries: a searchable and citable resource to disseminate virus taxonomy advances.

Taxonomic classification of cellular organisms requires the publication of descriptions and proposed names of species and the deposition of specimens. Virus taxonomy is developed through a different system of annual submission of formal taxonomy proposals (TPs) that can be submitted by anyone but are typically prepared by a study group appointed by the International Committee on Taxonomy of Viruses (ICTV) and consisting of experts on a particular group of viruses. These are initially evaluated by an expert subcommittee and by the executive committee (EC) of the ICTV.

Complete genome of five phages.

tailed phages Bhz9, Bhz15, Bhz16, Bhz20, and Bhz21 were isolated from wastewater samples in Hamburg-Eppendorf (Germany). Their double-stranded DNA genomes range from 41,054 to 167,277 bp, encoding between 54 and 267 predicted genes, with a G + C content ranging from 36.4% to 48.

and comparative analysis of 79 clinical isolates.

is a significant nosocomial bacterial pathogen that poses a substantial infection risk due to its high resistance to antibiotics and ability to survive in hospital environments. In this study, we performed comprehensive and analyses on clinical isolates from different geographical locations to uncover their genomic and epidemiological characteristics as well as their antibiotic and phage susceptibilities. Our findings revealed considerable genomic diversity among the isolates, as shown by average nucleotide identity (ANI) heat maps, multilocus sequence typing (MLST), and core genome MLST (cgMLST).

taxMyPhage: Automated Taxonomy of dsDNA Phage Genomes at the Genus and Species Level.

Background: Bacteriophages are classified into genera and species based on genomic similarity, a process regulated by the International Committee on the Taxonomy of Viruses. With the rapid increase in phage genomic data there is a growing need for automated classification systems that can handle large-scale genome analyses and place phages into new or existing genera and species.

Materials And Methods: We developed , a tool system for the rapid automated classification of dsDNA bacteriophage genomes.

Virus species names have been standardized; virus names remain unchanged.

Virus taxonomy, comprising classification and nomenclature, is regulated by the International Committee on Taxonomy of Viruses (ICTV). Taxon names are standardized to facilitate recognition and communication, with defined suffixes for each rank (e.g.

Impact of dairy calf management practices on the intestinal tract microbiome pre-weaning.

Microbiota in the gastrointestinal tract (GIT) consisting of the rumen and hindgut (the small intestine, cecum and colon) in dairy calves play a vital role in their growth and development. This review discusses the development of dairy calf intestinal microbiomes with an emphasis on the impact that husbandry and rearing management have on microbiome development, health and growth of pre-weaned dairy calves. The diversity and composition of the microbes that colonize the lower GIT (small and large intestine) can have a significant impact on the growth and development of the calf, through influence on nutrient metabolism, immune modulation, resistance or susceptibility to infection, production outputs and behaviour modification in adult life.

GRAViTy-V2: a grounded viral taxonomy application.

Taxonomic classification of viruses is essential for understanding their evolution. Genomic classification of viruses at higher taxonomic ranks, such as order or phylum, is typically based on alignment and comparison of amino acid sequence motifs in conserved genes. Classification at lower taxonomic ranks, such as genus or species, is usually based on nucleotide sequence identities between genomic sequences.

Resistance to bacteriophage incurs a cost to virulence in drug-resistant .

is a critical priority pathogen for novel antimicrobials (World Health Organization) because of the rise in nosocomial infections and its ability to evolve resistance to last resort antibiotics. is thus a priority target for phage therapeutics. Two strains of a novel, virulent bacteriophage (LemonAid and Tonic) able to infect carbapenem-resistant (strain NCTC 13420), were isolated from environmental water samples collected through a citizen science programme.

and evaluation of the biofilm-degrading phage Motto, as a candidate for phage therapy.

Infections caused by are becoming increasingly difficult to treat due to the emergence of strains that have acquired multidrug resistance. Therefore, phage therapy has gained attention as an alternative to the treatment of pseudomonal infections. Phages are not only bactericidal but occasionally show activity against biofilm as well.

Bacteriophage Taxonomy: A Continually Evolving Discipline.

While taxonomy is an often underappreciated branch of science, it serves very important roles. Bacteriophage taxonomy has evolved from a discipline based mainly on morphology, characterized by the work of David Bradley and Hans-Wolfgang Ackermann, to the sequence-based approach that is taken today. The Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) takes a holistic approach to classifying prokaryote viruses by measuring overall DNA and protein similarity and phylogeny before making decisions about the taxonomic position of a new virus.

Genomic Analysis of Two Novel Bacteriophages Infecting and Species.

Bacteriophages are the most diverse genetic entities on Earth. In this study, two novel bacteriophages, nACB1 ( morphotype) and nACB2 ( morphotype), which infect and , respectively, were isolated from sewage samples. The genome sequences of nACB1 and nACB2 revealed that their genome sizes were 80,310 bp and 136,560 bp, respectively.

Four principles to establish a universal virus taxonomy.

A universal taxonomy of viruses is essential for a comprehensive view of the virus world and for communicating the complicated evolutionary relationships among viruses. However, there are major differences in the conceptualisation and approaches to virus classification and nomenclature among virologists, clinicians, agronomists, and other interested parties. Here, we provide recommendations to guide the construction of a coherent and comprehensive virus taxonomy, based on expert scientific consensus.

Abolishment of morphology-based taxa and change to binomial species names: 2022 taxonomy update of the ICTV bacterial viruses subcommittee.

This article summarises the activities of the Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses for the period of March 2021-March 2022. We provide an overview of the new taxa proposed in 2021, approved by the Executive Committee, and ratified by vote in 2022. Significant changes to the taxonomy of bacterial viruses were introduced: the paraphyletic morphological families Podoviridae, Siphoviridae, and Myoviridae as well as the order Caudovirales were abolished, and a binomial system of nomenclature for species was established.

Complete Genome Sequence of Pseudomonas Phage Motto.

We describe the complete genome sequence of bacteriophage Motto, which infects clinical strains of Pseudomonas aeruginosa. Motto is a T1-like siphovirus related to members of the family and has a capsid width of ~57 nm and a tail length of ~255 nm. The 49.

ICTV Virus Taxonomy Profile: 2022.

Members of the family are lytic bacterial viruses infecting representatives of the bacterial class Gammaproteobacteria. Chaseviruses have a global distribution. Virions of members of this family have a myovirus morphology (icosahedral head with contractile tail).

Genomic Diversity of Bacteriophages Infecting the Genus .

The number of sequenced phage genomes in the International Nucleotide Sequence Database Collaboration has increased significantly in recent years, from 37 in 2017 to a total of 139 as of January 2021 with genome sizes ranging from 31 to 378 kb. Here, we explored the genetic diversity of the phages using comparative genomics approaches that included assessment of nucleotide similarity, shared gene content, single gene phylogeny, and the network-based classification tool vConTACT2. Phages infecting are genetically diverse and can be grouped into 8 clusters (subfamilies) and 46 sub-clusters (genera), of which 8 represent genomic singletons (additional genera).

Diversity of carbapenem-resistant and bacteriophage-mediated spread of the Oxa23 carbapenemase.

Carbapenem-resistant are prevalent in low- and middle-income countries such as Egypt, but little is known about the molecular epidemiology and mechanisms of resistance in these settings. Here, we characterize carbapenem-resistant from Alexandria, Egypt, and place it in a regional context. Fifty-four carbapenem-resistant isolates from Alexandria Main University Hospital (AMUH), Alexandria, Egypt, collected between 2010 and 2015 were genome sequenced using Illumina technology.

Phage Annotation Guide: Guidelines for Assembly and High-Quality Annotation.

All sequencing projects of bacteriophages (phages) should seek to report an accurate and comprehensive annotation of their genomes. This article defines 14 questions for those new to phage genomics that should be addressed before submitting a genome sequence to the International Nucleotide Sequence Database Collaboration or writing a publication.

Bacterial Viruses Subcommittee and Archaeal Viruses Subcommittee of the ICTV: update of taxonomy changes in 2021.

In this article, we - the Bacterial Viruses Subcommittee and the Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) - summarise the results of our activities for the period March 2020 - March 2021. We report the division of the former Bacterial and Archaeal Viruses Subcommittee in two separate Subcommittees, welcome new members, a new Subcommittee Chair and Vice Chair, and give an overview of the new taxa that were proposed in 2020, approved by the Executive Committee and ratified by vote in 2021. In particular, a new realm, three orders, 15 families, 31 subfamilies, 734 genera and 1845 species were newly created or redefined (moved/promoted).

A Roadmap for Genome-Based Phage Taxonomy.

Bacteriophage (phage) taxonomy has been in flux since its inception over four decades ago. Genome sequencing has put pressure on the classification system and recent years have seen significant changes to phage taxonomy. Here, we reflect on the state of phage taxonomy and provide a roadmap for the future, including the abolition of the order and the families , and .

From Orphan Phage to a Proposed New Family-the Diversity of N4-Like Viruses.

Escherichia phage N4 was isolated in 1966 in Italy and has remained a genomic orphan for a long time. It encodes an extremely large virion-associated RNA polymerase unique for bacterial viruses that became characteristic for this group. In recent years, due to new and relatively inexpensive sequencing techniques the number of publicly available phage genome sequences expanded rapidly.

Taxonomy of prokaryotic viruses: 2018-2019 update from the ICTV Bacterial and Archaeal Viruses Subcommittee.

This article is a summary of the activities of the ICTV's Bacterial and Archaeal Viruses Subcommittee for the years 2018 and 2019. Highlights include the creation of a new order, 10 families, 22 subfamilies, 424 genera and 964 species. Some of our concerns about the ICTV's ability to adjust to and incorporate new DNA- and protein-based taxonomic tools are discussed.